Loss of follicles during the follicular phase of the estrous cycle of swine as affected by genetic group and level of feed intake.

One hundred and .tWO puberal gilts from nine genetic groups were used to determine the association of two morphological types of Ovarian follicular loss (hemorrhagic and milky) with genetic background of ~gilts, level of feed intake and stage of estrous cycle. At estrus (day 0 of estrous cycle) a lesser prqportion of gilts (P<.05) had hemorrhagic foiiicles than gilts at day-15. While the total number of follicles decreased from day-15 to estrus (P<.01), the proportion of milky follicles increased (P<.01). No milky follicle was larger-than 6 mm in diameter. The high level 9f feed intake increased (P=.06) the number Of large follicles (7 to 10 ram), their average mean diameter (P<.05) and the proportion of gilts with hemorrhagic follicles (P<.05). Although the proportion of milky follicles did not differ significantly between the feed groups, the regression of the average number of large follicles on the average percent milky was negative ( .26) and